Two-cycle scavenging engine, supercharging



July 19, 1949. c. ELUCKE TWO-CYCLE SCAVENGING ENGINE .SUPERCHARGING Filed March 23, 194e' y 3 Sheets-Sheet 1 INVEN TOR.

CHARLES LU CKE c`. E. LUCKE TWO-CYCLE SCAVENGING ENGINE .SUPERCHARGING Jully 19, 1949.

:s sheets-sheet 2 Filed March 25, 1946 IN1/ EN TOR.

CHARLES E. LUCKE C. E. LUCKEv TWO-CYCLE SCAVENGING ENGINE SUPERCHARGING July 19, 1949.

5 sheets-sheet 5 Filed March 25, 1946 IN V EN TOR.

CHARLES E. LU CKE Patented July 19, 1949 TWO-CYCLE' SCAVENGING ENGINE, SUPERCHARGING Charles E. Lucke, New York, N. Y., assigner to Worthington Pump and Machinery Corporation, Harrison, N. J., a corporation of Delaware. 1

Application March 23, 1946, Serial No. 656,634

This invention relates to power plants, and more particularly to an internal combustion engine of the two cycle type.

An object of the present invention is to provide an internal combustion engine of the fuel injection, two cycle type wherein the construction is such as to secure a much higher power per cylinder than has heretofore been possible. g

Another object is to provide an engine wherein the temperature of the metal parts and the lu bricating oil film may be held within safely low temperature limits in spite of large increase in horsepower per cylinder.

Another object is to provide an engine which operates with a high degree of efficiency while developing a high horsepower per cylinder and at the same time keeping the temperature of the working parts within safe limits.

To attain the foregoing objects, mechanical means of great simplicity are provided for establishing conditions fundamental to the desired results. Increase of density ofV the air charge at the beginning of compression in the engine is the basis of a higher means effective pressure and hence of increased horsepower per cylinder.v Increase of scavenging air ratio, the ratio of volume of air to the piston displacement' as mean pressure is increased through air density, is the basis of limiting rise of temperature of the metal parts in .spite of the higher rates of heat gen eration.

The desirable results attained by the present invention are particularly useful in the simplest In contradistinction to the conventional engine of the foregoing class, the present invention embodies a scavenging pump, preferably of the centrifugal type, single or multi-stage, capable of being operated at high enough speed to develop a relatively high air pressure, for example, two atmospheres absolute, more or less. To make use of such high air charging pressures, valved means are employed to raise the back pressure, so that the pressure at the beginning yof compression may be substantially higher than theback. pressure,

12. Claims. (Cl. 12S-65) means being provided to always keep the air back pressure. The excess ofthe air pressure over the back pressure determinesv the quantity of air that ows through the cylinder while the inlet valve is opened, fand the heat abstracted from the hot faces of the metal bounding the working charge will be increased as quantity of excess scavenging air is increased.y Means Aare provided to control the excess scavenging ratio..

by increasing the excess of air pressure over the back pressure as back pressure is raised to increase the density of the cylinder charge. and mean effective pressure. Thus, the increase in mean effective pressure by increase in air density is made safely usable by correspondingly increasing the internal face heat abstraction asthese faces receive more heat. The scavenging pump is therefore also a supercharger.

The increase of mean pressure and horsepower per cylinder resulting from a higher back pres.- surev with a correspondingly still higher airv pressure, requires more horsepower to drive the scavenger-supercharger than otherwise, and this is subtracted from the horsepower developed by the engine proper because .the air compressor is to be driven by the engine, and the eiliciency may be expected to decrease as the net brake mean effective pressure rises. For some engine application purposes this is a real advantage and no serious disadvantage as it results in a light, compact and cheap engine, even if not of highest effi,- ciency.

However, should high Yefficiency be also a desirable factor in the operating conditions, it can be obtained in the present engine without anyv changes, by merely adding an exhaust gas turbine with valved nozzles replacing the valved back f turbine through control of the scavenging ratio by the maintained rise of excess air pressure over back pressure and corresponding excess of air with increase of engine load. The excess of 'air limits the temperature'of lexhaust gas by air dilution.

With these and other objects in View, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accom.n panying drawings, showing a power plant of a preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawings:

Figure l is a, diagrammatic view of an internal combustion engine in accordance withthe present invention, with parts thereof shown in section for the purpose of illustration.

Figure 2 is a view taken from the position indicated by the line 2--2 of Figure l.'

Figure 3 is a view similar to Figure l but illustrating a pressure responsive control for mainn taining an excess of air pressure over back presn sure for all values of one of thesepressures.

Figurefl isa view similarto Figure lbut illusu trating aA gas turbine arranged to utilize the exhaust gases from the engine. A .i

Figure 5 Ais a view taken from the position indicatedby the line 5-5 of Figure 4.

.Figure 6 Ais ,anV enlarged sectional view ofthe gas turbine nozzle arrangement.

Figure 'Z is a View of the parts of Figure 6 but rotated 90 about avertical axis.

Figure 8 is a diagrammatic View of a form of airport arrangement.

Figure 9 is a diagrammatic view illustrating theinlet and exhaust ports extended all around the cylinder in two belts... l

Figure 10 lillustrates an engine `wherein exhaust port is utilized.

Figure 11 illustrates an engine embodying -a valved inlet port.

diierent a valved 4 the exhaust ports 2! are opened before and closed later than the inlet ports 30. All the ports 3) take air from the air manifold '29, and the valve or throttle 28 controls the air pressure in the manifold 29, which throttle may. be operated manually or by the engine governor (not shown) so as to insure that the engine cylinder will always have sufficient air charge to completely burn all of the fuel injected in accordance with the. Yload requirements, manually for variable speeolengines and by the governor for constant speed engines7 consistent with the fuel oil injected. Y

Y All theexhaust ports 2i deliver to the exhaust manifold 22, and a back pressure valve or throttle 33 is provided in the pipe 23, which valve may be opened or closed to contro] the back pressure in the exhaust manifold `.22, as desired. An es sential feature ofthe present invention is the maintenance of an excess of air pressure over the back pressure for all values of one of these pressures, and an increasing excess as the air pressurelisraised for higher mean effective pres- `-sures to insure a correspondingly larger excess scavenging ratio to` control the exhaust' gas temperature and'insure adequate internal cooling of the` working i parts. One mechanical means 0f accomplishing this is shown diagram- Figure 12 illustrates an engine structure embodying two opposed pistons which may operate to open and close inlet and exhaust ports with the same timing difference-as characteristic of Figure 11. i v if In ,the embodiment of` the invention selected for illustration, Figure .1 illustrates an interna-l,vr

combustion engine i4 which is of the two cycle, compression ignition or Diesel type. This engine includes the usual cylinder l5 having a bore I5 within which` the piston. l1 is slidablyguided, which piston is operatively connected .with the crankshaft i8 in the usual manner. Oil fuel is introduced into the combustion chamber i9 through a fuel injection nozzle 2li such as, isused for Diesel engine purposes.4 Exhaust ports .2! open from the combustion chamber I9 and comN municate with an exhaust manifold 22, which in turn delivers the exhaust gases into an exhaust pipe or conducting means 23.

A scavenger-supercharger 24which comprises a centrifugal air compressor, has its rotor shaft" 25 geared to the crankshaft IB to be driventhereby, the two shafts being drivingly connected by a gear train 26. Y

scavenging and supercharging air flows from the machine 24 to the combustion chamber lil through a pipe `or air conducting means 21.

r, lll:

valve or throttle 28 is incorporated in the pipe Vmatically in Figure l, the air throttle'4 28, man,-

ually operated or operated by a governor (not shown), controls the air supply to the air manifold 29, and for a given setting of the backv pressure valve 33,' opening of the air throttle valve 23` will raise thepress'ure in theair manifold 29, as may be indicated by the air pressuregauge 3l.

In Figure 3 the back pressure valve 33 is actuated by a piston 34 slidably guided in cylinder 35. A rod 35 is fixed to a piston andhas one end extended toV aposition externally of the cyl-- inder 35 for connection with acrosshead 3l. One end of a link'lg is pivotally connected with the crosshead 3l and its other end is p ivotally oonnected 4with a lever 39 attached to the back pressure valve33. A

A second cylinder 4i! is connected in co-axial relationship with the cylinder 35 and contains a piston r4l which is ixed to the other end of the Y piston rodv 35. Between the piston 4l and a stop 42 is interposed a compression spring 43 the tension of which may be changed through adjustment of a screw 44 which is threaded through one end Vof the cylinder 40 and arranged in engagement with the stop 42. A pipe or conducting means 45 communicates with the air manifold 29 and has a branch `4&5' which opens into the chamber @1in the cylinder 35. The pipe 45 includes a second branch 48 which opens intothe chamber 49 ofthe cylinder 433. Vents 5 are provided in cylinder 4G opposite the chamber 49 to permit frere movement Vof the piston 4I. A conduit or conveying means 5l .leads from the exhaust pipe 23 and opens. into the chamber 52 in the cylinder 35, with the pipe 5I having communication Awith the exhaust pipe at a point between the exhaust manifold '22 and the back pressure valve 33. Adjustable valves 53 and 54 are interposed in the conduit 45 on opposite sides of the branch 48 so that the ow of compressed air to the chamber 49 may be controlled or shutn off through the adjustment of the valve 53. The valve 54 is normally adjusted to vent compressed air tothe atmosphere.

According to Figure 3 the air pressure acts on one side ofthe piston 34, while. the back pressure acts on the opposite side of the piston 34,

anche? I with thel spring 43% acting.- on the piston 4 t, tend;- ing: te more. the assembly tothe leftl supplementing;` the'force due to back pressure., The sunr oi thesel two forces being balancedby the.J air pressure,4 the air pressure must always be,4 greater than the back pressure by an amount` correspondin'g to the spring load which is adiustalole..V

The air. pressure is; also ledy to the chamber 492 which carries the. spring. 43,. thefjoint adjustment of thevalvesf 53: andi 5.4:: controlling the pres:-A

sur'e in 15h-aspiring. containing chamber and adds to: the spring load eective on the piston- 4I. at; alli times, but as.- the air pressure rises so. also will the. pressure in the spring containingchambcr andthe. supplement to the. spring load.. Infthis;-

manner the diierence between. the air pressure andzbachpressure will; increase as. air' pressure;` rises, thus insuring that the. excess scavenging ratio. that controlsinternal cooling .and exhaust gas temperature, wil-li rise with increase or cyl.- inder chargeA density, and mean effective kpressure..

Figures 4. and 5,A a gas. turbine 5.5 is associated with the engine.. t4; The exhaust gases delivered to the.l pipe or conducting means 2.3. are. utilized:forV driving the turbine 55. In 'utilizing the. exhaust gases. for turbine driving purposes;

the back'pressure valve. 33 is set in. its: wide open position or may-be omitted,

Exhaust gases enter the turbine .55 through the chest 56:, see Figure 6, and inlet valves 51 control theil'owr of gases through the passage 58 .andftothe nozzles of the turbine, the nozzle structurev of the. turbine. being. indicated generally at 59' 1n. Figure '7'. Since the inletvalves 51 are. adjustable.. andi' each controls gas admission. .to a different set or section of nozzles7 the effective nozzle area ofthe turbine may be regulatedL through adjustment of the valves.. Each valve is. opened by any independent cam 53. mounted ona camshaft 5.3; and' the cams. may be shaped to give any desired. rate or sequence of opening. vRotation ot the camshaft ll. imparts valveactuatingxmotion to the. cams 59, which rotation. can be controlled manually or by automatic devices, an actuating lever 6l being. illustrated inFigure- 'll for impart-- ing rotation to the camshaft.

The. rotor of .the turbine 55., shown fragmenftarily'at 62 in: Figure I and ascornprisingwheels; (i3I arranged in operative relationship with .the

nozzle structure 59, drives the rotor shaft 64 of.

Figures'4 and 5. A gearV .train 65 drivingly connects the rotor shaft 64 with the crankshaft I8.

Figures 8 through 12 illustrate other tWo cycle port. arrangements, some of. which may be. supercharged to some degree and in. which excess scavenging may be secured also to some degree, but to all of these the present invention is also applicableas an improvement.

'Figure 8 illustra-tes anengine cylinder 66. which is .providedwith an air inlet port 61 and: a secs ondary airinlet port 68.. The port 58 is arranged to be, opened' before andclosed. after the exhaust port 69,. but is. provided ywith a. valve YI0 which is forced to afclosed. position by pressure acting on its face when the cylinder pressure is higher than the air pressure..

In Figure 9, the inlet ports 'M and the exhaust portal? extend all around the cylinder 'l3'in two lines or planes, with the Voperation the same. as in an engine structure of. the type shown in Figure 1.

Figure 10 illustrates an engine cylinder 14 wherein a valvef'l is provided for exhaustfport 16, while in Figure 1.1, av valve 11i 'is provided for 6l the. port lli,A the valresl andvl'lf alliowing: di; relations .between eldia-.usty

and inlet. The timing diierence may beohtained inem engine strircturesuch as that shownin. Figure 12,-. wherein two opposed. pistons 19. aref. employed. and which the. inlet. ports 80.-

engine: power:- reduirements increase which.`

comprisescharging the. cylinders with. compressedairat, thebeginningicr. the compression stroke while. exhausting` burned. gases from the. cylinders andncreasing the pressure orthe charsing air/while increasing at ar lesser rate the re.- sistance tio-exhaust flow of theburned gases, said resistance being regulated so. that. theback. pressure of exhaust gases islessthanthe pressure. of.

charging air...-

2. InI acharging system for-the cylinders olf;v a

two cycle piston type internal combustion engine the combination of fexhaust conduits con nected.- to thexcylinders .for exhausting burned gases therefromyrst. means for delivering pres.- sure air to thetcylinders,.valve means in said exhaust. conduitsfor resisting: the. flow ofV burned gases therethrough, control. means for operating the valve meansfandmeans operatively connect.- ing the irstameans to the control means so that variationsv in the; pressure-of the air being cielivered toV the cylinders actuates the control means, said' control .means being constructed' and arrangedV sothat increases. inair pressure rirl-- crease the resistance;A ofthe valve means and the backpressurefo exhaust gases.. due to said rea sistance remains less thanthepressureo the air.

3. In- -a charging system -for the cylinders' of a two-cycle piston typeinternal combustion en-v gine as claimedv infclaim 2 wherein the control means 'isfconstructect and arranged to increase the resistanceand thus. the backpressure at a lesser ratey thanrthe rate of' increase of air pres.-

sure.

4. In a charging system for the cylinders ofV a twocycle! piston typev internal oombuson. engine the ycombination off'exhaust conduits connected to the cylinders. for exhausting burnedl gases therefrom, valve means in'said conduits for resisting` the flow f ofI burned; gasesv therethrough, pressure responsive*- means i for vactuating said valvemeans to. increase. the resistance. as the pressurefthereon-l is increased, means for delivering charging pressureair to the cylinders, and means? operativelyv connecting said last mentioned means to thefpressure responsive means so that-.pressure asractuates the same, said pressure responsivemeans beingconstructed and ar- Y f air pressure.

6. In. a charging system 'for the cylinders of two-cycle piston-type internal combustion engines the combination of exhaust conduits connected to the cylindersv for exhausting burned gases therefrom, valve means in said conduits for resisting the flow of burned gases therethrough, pressure responsive means for actuating said valve means to increasefthe resistance as the pressure thereon 4is increased, means for delivering charging pressure air to the cylinders, means for delivering charging pressure air from said pressure air delivering means to said pressure responsive means, means for delivering exhaust gases from said exhaust conduits to said pressure responsive means whereby the pressure responsive means will be under opposed pressure of charging pressure air and exhaust gas pressure, pressure exerting means cooperating with the exhaust gases in said pressure responsive means so that the back pressure of the exhaust gases is less than the pressure of the charging air.

7. In a charging system for the cylinders of two-cycle piston-type internal combustion engines the combination of exhaust conduits connected to the cylinders for exhausting burned gases therefrom, valve means in said conduits for resisting the flow of burned gases therethrough, pressure responsive means for actuating said valve means to increase the resistance as the pressure thereon is increased, means for delivering charging pressure air to the cylinders, means for delivering charging pressure air from said pressure air delivering means, means for delivering exhaust gases from said exhaust conduits to said pressure responsive means, said pressure responsive means embodying differential areas the larger of which is exposed to opposing pressures of charging air and exhaust gases and the smaller of which is exposed to pressure of charging air, the charging air pressure on the smaller area cooperating with the exhaust gas pressure on the larger area in opposition to the charging air pressure on the larger area.

8. In a charging system for the cylinders of two-cycle piston-type internal combustion engines the combination of exhaust conduits connected to the cylinders for exhausting burned gases therefrom, valve means in said conduits for resisting the ilow of burned gases therethrough, pressure responsive means for actuating said Lil Valve means to increase the resistance as the pressure thereon is increased, means for delivering charging pressure air to the cylinders, means for delivering charging pressure air from said pressure air delivering means tov said presssure responsivemeans, means for delivering exhaust pressure air delivering means to said pressure responsive means, said pressure responsive means embodying differential areas the larger of which is exposed to opposing pressures of charging air and exhaust gases and the smaller of which is exposed to pressure of charging air, the charging air pressure on the smaller area cooperating with the exhaust gas pressure on the larger area in opposition to the charging air pressure on the larger area, and tensioned pressure exerting means exerting pressure on said smaller area in cooperation with the pressure of charging pres- 9. In a charging system for the cylinders of a two-cycle piston-type internal combustion engine as claimed in claim 8, means for adjusting the tension of said tensioned pressure exerting fmeans to vary the ratio of difference in increases in back pressure and pressure of charging air.

10. The method of air charging the cylinders of a two-cycle piston type internal combusticn engine as power requirements for a given Speed increase, which comprises charging compressed nected to the cylinders for exhausting burned gases therefrom, valve means in said conduits for resisting the flow of burned gases therethrough, pressure responsive means for actuating said valve means to increase the resistance as the pressure thereon is increased, means for delivering charging pressure air to the cylinders, means for delivering charging pressure air from said pressure air delivering means .to said pressure responsive means, means for delivering exhaust gases from said exhaust conduits to said pressure responsive means, said pressure responsive means embodying differential areas subjected to the pressure of charging air and pressure of exhaust gases plus pressure of the charging air whereby the resistance of the valve means will be regulated so that the back pressure of the exhaust gases is less than the pressure of charging air and the back pressure of the exhaust gases will be increased at a lesser rate than the increase of pressure of charging air.

12. A charging system for the cylinders of a two-cycle piston-type internal combustion engine as claimed in claim 11 including tension pressure exerting means for exerting pressure on one of said diierential areas and means for adjusting the tension of said tension pressure exerting means to vary the ratio of difference in increases in back pressure and pressure of charging air.

CHARLES E. LUCKE.

REFERENCES CITED The following references are of record in the file of this patent: v

UNITED STATES PATENTS Number Name Date 1,211,746 Nordstrom Jan. 9, 1917 1,320,062 Junkers Oct. 28, 1919 1,321,392 Reale Nov. 11, 1919 1,354,786 Tartrais Oct. 5, 1920 1,530,414 Romeyn Mar. 17, 1925 2,023,403 Butler Dec. 10, 1935 2,044,552 Walti June 16, 1936 2,088,215 Podrabsky July 27, 1937 2,126,860 Alfaro Aug. 16, 1938 2,164,167 Schneider June 27, 1939 2,199,259 Hersey Apr. 30, 1940 FOREIGN PATENTS Number Country Date 262,044 Great Britain 1926 347,118 Great Britain 1931 j combustion 

